code: def kernel_pdf_recipinvgauss_(x, sample, bw):
      """Reciprocal inverse gaussian kernel density, explicit formula.
  
      Scaillet 2004
      """
  
      pdf = (
          1
          / np.sqrt(2 * np.pi * bw * sample)
          * np.exp(
              -(x - bw) / (2 * bw) * sample / (x - bw)
              - 2
              + (x - bw) / sample
          )
      )
      return pdf
  
imports: import numpy
  from scipy import special, stats
label_desc: Use image node_id 19 for calling a global function with example usage: kernel_pdf_recipinvgauss_(x, sample, bw) and returns: pdf